Shadowy figure from Irish mythology, Ler (also spelled Lir) is generally believed to be god of the sea (as the Gaelic word "ler" means "sea"), a role also ascribed to his son Manannan mac Lir. He is rarely mentioned in the existing myths, excepting one tale, "The Sorrow of the Children of Lir".

In Welsh mythology, he is called Llyr, which sounds about the same. In British legend, he is called Leir, the spelling changed to Lear in Shakespeare's time. He is the origin of Shakespeare's King Lear.